1. Field of the Invention
This invention relates to equipment used for athletic exercise, and more particularly, to portable devices used to exercise and strengthen the muscles by pulling.
2. Background
A portable athletic exerciser pulling device was invented earlier and is described in U.S. Pat. No. 5,505,681 by Bruggemann, who is one of the present inventors. This patented device consists of a small cylindrical housing enclosure containing a number of constant force, circular wound spring assemblies; and includes a cord-wound pulley wheel with a pull handle, that is molded to the enclosure and an attached force selector mechanism. The selector is used to manually select the number of spring assemblies to be engaged by the pulley, by inserting and moving a splined rod axially to connect in turn with the axially stacked spring assemblies.
When the pull handle is pulled, the device housing rotates around its cylindrical axis as do all the spring assemblies inside the housing. However, the total resisting force felt by a user is determined by the number of spring assemblies selected, as well as their individual constant force ratings.
If five spring assemblies are contained in the housing, then the maximum number of resisting force levels available to a user is also five. This is due to the sequential method of spring assembly selection employed by the device.
While the device described above has performed admirably and has been well received by users, the inventors believe that the number of resistance force levels made available by the device is unnecessarily limited, and the device remains more costly to produce than desired. There is, therefore, a need to improve upon the design of the device to extend the device versatility and at the same time, decrease the cost of the device.